Method of making reamers



J. V. EMMQNS June 29 1926. A 1,590,184

METHOD OF MAKING REAMERS v Filed June 25. 1925 i IZ f l V L W M INVENTOR. gg, i gyosel/I Vmzzzozz ATTORNE 5.

Patented June 29, 1926..

UNITED STATES PATENT olulcls.-v

JOSEPH V. EMLIONS, OFVSHAKER HEIGHTS,v OHIO, ASSIGNOR TO THE CLEVELAND TWIST DRILL COMPANY, OF CLEVELAND, OEIO, CORPORATION OF OHIO.

METHOD or MAKING annuliens.

Application led June 25, 1925. Serial No. 39,531.

The present improvements relate more .particularly to a method for manufacturing spiral finte expansion reamers which differA from the ordinary s iral flute or helical reamer in that the bo y of the tol, instead of being solid, is bored out and slits cut in the spiral flutes so as to permit Aof the expansion of the blades by forcing a pointed or tapered pin within the bore of thetool. More or less difficulty has been encountered in the manufacture of this type of reamer due to the fact that the necessary slots between the blades can not sbc* readily cut to the required depth on a helix or spireinasmuch as a'saw is conveniently employed for this operation and if the twist of the helixv be too great, such saw will either bind or break.A

The object of the present invention accordingly is to provide a method wherein the slots, as well as the flutes, may be cut straight and the necessary inclination or curvature thereafter `imparted thereto by appropriately twisting the body of the reamer. A further object is to prevent the partial closure o f the slots and the tendency of the blades to become distorted during such twisting operation.

To the accomplishment of the foregoing and related ends, said invention, then, consists of thesteps hereinafter Vfully described and particularly pointed out in the claims, the annexed drawing andthe following descri tion setting forth in detail, certain mec anism embodying the invention, such disclosed means constituting, however, but one of Various mechanical formsf in which the principle of the invention may be used.

In said annexed drawing Fig. 1 is a side elevation of a blank or piece of stock such as is employed in making a reamer according to the present improved method, the body of such blank being shown with the above mentioned slots already cut therein; Fig. 2 is a transverse section of the reamer thus slotted, the plane of the section being indicated. by the Aline 2-2,4Fi 1; Fig. 3 is a similar side elevation o the reamer after the body has been provided with the necessary tintes; Fig. 4 is a trans rally flutedbody portion 3. VOne such end vreduced-at an intermediate point 7 so that verse section of the same, the 'plane of'the section being indicated by the line 4.-4, Fig. 3; Fig. 5 is partly a side elevation and partly an axial section of the reamer after it has been thus slotted and fluted, such section also showin the central opening or bore with which t e reamer is provided; Fig. 6 is a transverse section of the same, the plane of the'section .being indicated by the line 6-6, Fig. 5; Fig. 7 1s ,a view similar to that 50 of Fig. 5, but showing a mandrel inserted in the bore preparatory to the twisting operation; Fig. Sis a side elevation of the fin? ished reamer; and Fig. 9 is a section showing a modification.

Asillustrated in Fig. 8, which shows the finished article, the latter comprises two end portions 1 and 2 and an intermediate, spiportion is left solid andis provided with 7o a squared projection or tang l whereby the reamer. may be secured in a suitable chuck.

.Extending from the other end 2, through the body 3 of the reamer, is a central bore 5, which is shown only in dotted outline in the elevational view of Fig. 8. i

Referring particularly' to such lastmentioned figure, the outer portion 6 of the bore is internally threaded and, its diameter is by means of a pin (not shown), provided with external threads to engage such threads 6 and with a pointed or tapered end to engage such reduced portion 7 of the bore, the, body of the reamer may be expanded as required in use.

The first step in the manufacture of the j reamer starting with a blank as shown in Fig. 1, except for the slots inthe body portion of such blank, is to cut the desired number of such slots 10, four being illustrated in the casein hand, (see Fig. 2). Theseslots, as previously stated, are cut with a saw, and since they are straight and lie longitudinally of the reamer body they may be very quickly 5\ and easily made. It should be stated at this point that while the bore 5 is preferably formed at a later sta e in the operation'it may, if desired, be formed previously to the aforesaid slotting step, .in which event the 10 A451 complish the object desired, which is to proslots 10 may be cut through into such bore, or they ma be cut to a corresponding depth if the bla is left solid, or they may be cut through until they meet in the. case of such solid blank.

Following the cutting of the slots 1() :in the manner just described, the blades llvare -formed byI milling a iute or channel on one side of each of such slot, and inasmuch as there will ordinarily be more flutes than slots, such `additional iiutesas may be desired will be milled betweeneach pair of adjacent slots. Such flutes, it will b e vunderstood, are'milled straight and this milling operation ma accordingly be quickly and.

` easily accomp shed.

conform to the curve about such body which they should follow in the finished article.

The reamer, or at leastY the body portion tl1ereof,.is preferably although not necessarily heated preliminarily to such twisting operation and, if desired,I temporary filler strips corresponding to the metal removed 'by the 'saw may be inserted in the slots in' order to prevent them from becoming closed incidentally to the twistin operation. ,The latter may be convenient y performed by gripping the respective ends 1 and 2 between jaw members capable of relative r0- tative movement.

The use of filler strips in the manner just f referred to is not presented as new in the present connection. Furthermore, it has f been found in practice that such strips are unsatisfactory, at least by'themselves, to acvent distortion of the' blades due to the tendency of the portions of the body thatl lie between the slots to" contact into the bore incidentally to the twisting operation. Accordingly, in order eiectively to overcome this tendency I employ the'mandrel 12, as shown in Fig. 7 This mandrel consists of a pin or rod that is turned to have the same external conformation as the interiorv of the bore 5, although it is not necessary that the extremity o the rod project entirely to the end of inner portion of the bore of smaller diameter. vIn other words,

such mandrel may terminate shortJ of such -.bore-end as shown. This mandrel may be externally supported in any suitable manner alnst endwise movement, v

so as to be held while the ends o the reamer are rotated relativel to each other in the manner' just' describe As la result the portions of the 'reamer body intermediate of the slots 10 will be supported just as effectively as if the bore had not been previously formed, and the tendency for the body andthe blades to become distorted is substantially entirely eliminated.

^ After the twisting operation the mandrel is of course removed, the filler stri s, if these have been used, likewise remove and the body of the tool hardened in the usual manner. The finished tool will then present the appearance illustrate in Fig. 8.

As an alternative to thus inserting the mandrel 12 in the bore of the tool and there holding the sameduring the twisting operation, the body of the reamer ma be twisted Without the mandrel and the lyatter thereupon inserted and the reamer body 'expanded so as again to open the slots in case they have become closed or partially closed in the twisting process. This will preferably be done while the metal is still h'ot so that the parts of the body affected may be readily displaced to occupy their original proper positions. While in Fi 7, the mandrel 13 is shown as inserted in llore 5 in its nal form comprising two sections, one of lar r -diameter than the other, it may be ound desirable to leave such bore of single, i.. e. smaller, diameter until after the twisting step. In other words, th'eA body wall adv jacent the portion of the bore of larger diameter, as will ap' ear from an inspection of Fig,7, is consi erably thinner than the body wall adjacent the smaller bore diameter, and there will be a corresponding tendency for vthe first mentioned portion of the body to twist morel than the other. `Accordingly, as shown in Fig. 9, the bore 13 may be left throughout of initial smaller diameter and a mandrel 14 of corresponding diameter employed in such twisting step, so as to insure a uniform effect throughout the length of the mandrel body. Such bore 13 will then be subsequently enlarged at its -outer end, reamed to provide the, bevel portion, and threaded at its outer end, exactly as shown in Fig. 6. Othermodes of'a plying the principle of my invention may e employed instead of 'i the onelexplained, change being made as regards the mechanism herein disclosed, provided the means stated by any of the ollowing claims or the equivalent of such.'`

stated m be empl ed.

v I there re particu arly poi't outand distinctly claim as my invention j 1. In a method of making a spirallute expansion reamer,` the steps which consist in roviding a central bore and lon 'tudinal y extending slots and flutes 1nv thereamer body, the requisite operations performed 1n any desired order, and then twisting said body to impart the desired lio spiral angle to such slots and utes, a manbody, the requisite operations being perv`drel being inserted in such bore as and for formed in an desired order, `inserting a the purpose described. f mandrel in suc' bore, and then twisting said l0 2'. vIn a method of making a spiral iiute body to impart the desired spiral angle to 5 expansion reamer, the steps which consist in such slots and utes. l e

providing a central bore and lon itudinally Slgned by me, this 23 day of June, 1925 extending slots and flutes in t e reamer JOSEPH V. EMMONS. 

